Animals and neonatal treatment with MK-801
All our experimental procedures were carried out in rigorous accordance
with the ”NOM-062-ZOO-1999” local regulation for the use and care of
laboratory animals and the protocols authorized by the internal ethics
committee (CICUAL) of our institution (CINVESTAV; Protocol number
0090-14), which mandate the minimization of suffering and the number of
experimental animals used. These regulations and protocols are
consistent with the ARRIVE 2.0 guidelines, the recommendations made by
the British Journal of Pharmacology (Lilley et al., 2020), and the
National Institutes of Health (US) guidelines for animal care.
Pregnant Wistar rats were supplied by our vivarium and given continuous
veterinary care. The rats were housed in the following control
conditions: an inverted light-dark cycle (12 h; the light was turned off
at 10:00 h), a room temperature of 23 ± 1° C, and free access to food
and water. The pups’ birth was designated as postnatal day 0 (P0), and
animals were kept with their mothers until P21. The experimental
procedures were performed in two cohorts of male animals ranging from 30
to 38 days old. Each experimental manipulation was carried out in at
least three different litters. From P7 to P11, the animals received
daily subcutaneous injections of either saline solution (SS, 0.9%) or
MK-801 (0.2 mg/kg in a 2 mL/kg volume) (Griego et al., 2022; Márquez et
al., 2023). The behavioral procedures were carried out between 10:00 and
16:00 h. The experimental animals were treated with SS or MK-801,
following a single sequence of random assignments. The MK-801 was
dissolved in isotonic SS. Animal suffering was minimized during and
after the injections to reduce behavioral or neurophysiological
alterations that might affect the experimental results. In addition, the
assignment of animals to control and MK-801 groups was blind, to prevent
any potential bias.